In recent years, magnetic recording devices for computers, such as hard disks, have rapidly been downsized, and their capacities have been increased. The recording density of such devices is estimated to reach 20 Gb/in.sup.2 in a few years. Therefore, conventional induction-type heads used as playing heads have approached their limit, and alternatively, magneto-resistance-effect-type (MR) heads have begun to be used. Use of the MR heads is expected to grow rapidly in the future in a worldwide scale accompanying the growth of the personal computer market. In coming years, the practical use of giant magneto-resistance-effect-type (GMR) heads, expected for their further higher density, will be realized.
Ni--Fe alloys have been studied for use as a ferromagnetic film of the spin-valve film used in GMR heads.
Ni--Fe alloys are normally produced by sintering or melting. However, conventional Ni--Fe alloys release a large amount of gases, produce a large number of particles during sputtering, and have the problem of corrosion resistance. Also, their magnetic properties are not found to be satisfactory.